Gangway



Filed Feb. 28, 1967 2 Shee's-Sheet l FIC-3.!

rNvENTom Robert W. Conner BYM? ATTORNEY R. W. CONNER Dec. 3, 1968GANGWAY 2 Sheets-Sheet 2 Filed Feb. 28, 1967 FIG. 2

INVENTOR. Robert W. Conner ATTORNEY United States Patent O 3,413,671GANGWAY Robert W. Courier, Alvin, Tex., assignor to lvonsanto Company,St. Louis, Mo., a corporation of Delaware Filed Feb. 28, 1967, Ser. No.619,219 5 Claims. (Cl. 14-71) ABSTRACT OF THE DISCLOSURE A retractablegangway to provide access from a loading dock to a railroad tank carwherein the platform portion and counterweight converge. The gangwayretracts to a Vertical position when not in use.

Background of the invention The present invention relates to a gangwaywhich may be attached to a railroad tank car loading dock or the like.

In the loading of railroad tank cars, these tank cars generally arerolled into position on tracks running parallel to a loading dock. Thereis generally a walkway on top of the loading dock at substantially thesame height as the tank cars and numerous pipes and conduits underneaththe walkway for transporting fiuids from storage areas to the tank cars.These walkways, `as are the loading docks, are generally parallel to thetracks and do not come into contact with the tank cars. In loading atank car it is desirable for the workmen to have access from the walkwayon top of the loading dock to the top of the tank car and for thispurpose various gangways have been devised to bridge the space betweenthe walkway and the tank car. However, in order to permit tank cars andother trafiic to move freely along the tracks 'alongside the loadingdock, it is necessary that these gangways be retractable. One of themost common retractable gangways now in use consists of `a platformwhich is pivoted at a point intermediate the ends thereof and having acounterweight on one end of the platform. Such a gangway operates inseesaw fashion so that a workman desiring to use the gangway merelypushes the non-weighted end of the platform downward 'toward a tank carwhile the weighted end of the platform swings upward and away from thetank car. When the workman has finished using the gangway7 he merelysteps off the platform and the counterweight brings the platform to aVertical position so as to no longer extend over and interfere withmovement of tank cars on the tracks. While such a gangway is of simpleconstruction, it suffers the serious disadvantage that thecounterweighted end of the gangway must swing under the loading dock,and therefore, any piping under the walkway .must be specially designedto avoid the counterweighted end of the platform. Hydraulicallycontrolled gangways have also been constructed which do not interferewith piping under the loading dock walkway; however, these hydraulicallyControlled gangways lare undesirable in that they are expensive to buildand eX- pensive to maintain.

Summary It is thus an object of the present invention to provide agangway suitable for attachment to railroad tank car loading docks. ltis a further object of the present inven- 3,4l37l Patented Dec. 3, 1968ICC tion to provide a retractable gangway for a railroad tank carloading dock which is of simple construction and which Will notinterfere With piping underneath the Walkway of the loading dock.Additional objects will become apparent from the following descriptionof the present invention.

The present invention in one of the embodiments is a gangway forattachment to a structure comprising a platform having =at least onefirst spur gear fixedly attached thereto at one end of said platformsuch that substantially all of said platform extends away from the axisof said first spur gear, said platform being substantially parallel to aplane containing the aXis of said first spur gear, said first spur gearbeing meshed with at least one second spur gear, said second spur gearbeing fixedly attached substantially to one end of a frame extendingaway from the axis of said second spur gear, said frame having acounterweight secured thereto at a distance from the axis of said secondspur gear, 'both said platform and said frame being rotatably attachedto a member or members adapted to be mounted on said structure, saidplatform being rotatably attached to said member or members so as torotate about the axis of Said first spur gear and said frame beingrotatably attached to said member or members so as to rotate labout the'axis of said second spur gear, said first spur gear being meshed withsaid second spur gear such that Said frame will extend substantiallyvertically downward when said platform extends substantially verticallyupward.

Brief description o the figures FIGURE 1 is a side view of a gangwayconstructed in accordance With the present invention in a raisedposition.

FIGURE 2 is an isometric view of a gangway of the present invention in alowered position and also shows a type of side railing 'and lookingdevice which may be used with a gangway of the present invention. Thesame num- 'bers are 'used in both figures to denote the same elements.

Description of the invention Reference is now made to FIGURE 1 for anexplanation of the operation of the present invention. The gangway shownin FIGURE 1 consists of platform 1 having attached thereto spur gear 2such that platform 1 does not rotate with respect to spur gear 2. Meshedwith spur gear 2 is spur gear 3 from which extends frame 4 having acounterweight 5 secured thereto, frame 4 being fixedly attached to spurgear 3 so that spur gear 3 and frame 4 do not rotate with respect toeach other. Both platform 1 and frame 4 are rotat'ably attached tomember 6 so that platform 1 and frame 4 rotate about the aXis of spurgear 2 and the |`axis of spur gear 3 respectively. Member 6 is thenattached to a loading dock having a Vertical member 7 and a walkway 8.While platform 1 and frame 4 are shown as being attached to Verticalmember 7 through the use of a single member 6, it is obvious thatsep'arate members could be used to attach platform 1 and frame 4 toVertical member 7. The particular method by which platform 1 and frame 4are fixedly 'attached to spur gears 2 land 3 and rotatably attached tomember 6 is not a part of the present invention and can be easilyaccomplished by those skilled in the art. One obvious method is toprovide an 'axle through the spur gear such that the axle does notrotate with respect to the spur gear, and fixedly attaclhing platform 1or frame 4 to the 'axle while providing 'member 6 with a bearing orbearings on which the axle may rotate.

In using the gangway, a workman on walkway 8 merely depresses platform 1of the gangway outwardly of the walkway and downward and in turn frame 4travels outwardly of the walkway and upward as shown by the arrows. Ifthe gear ratio of spur gear 2 and 3 is 1:1 then platform 1 and frame 4will meet with both being horizontal as shown in FIGURE 2. The platformwill then be in the lowered position and will provide a bridge extendinghorizontally from walkway 8 on which workmen may travel. When' theworkman steps off platform 1, counterweight will pull frame 4 downwardand thus force platform 1 upward to the original raised position shownin FIGURE 1 wherein both platform 1 and frame 4 are Vertical so as tolpresent no obstacle to objects moving in close proximity to the loadingcar platform.

In constructing a gangway according to the present invention, only onespur gear is actiually needed for attachment to the platform portion andone spur gear for attachment to the frame portion but it is preferred tohave 'two spur gears on the platform portion of the gangway and two onthe frame portion of the gangway as shown in FIGURE 2. It is alsoobvious that as many -gears as are desired can be used. When using aplurality of gears on the platform and frame portions of the presentinvention, these gears must be axially aligned, i.e., all of the gearsattached to the platform portion must be axially aligned with each otherand all of the gears on the frame portion |must be axially aligned witheach other. It is preferred that the gear ratio of those gears on theplatform portion to those gears on the frame portion be 1:1 and thatthey mesh in such a manner that the frame portion on which thecounterweight is attached extends substanti'ally vertically downwardwhen the platform portion extends substantially vertically upward asshown in FIG- URE l. When the 'gears are in this ratio and are someshed, the frame and platform positions of the gangway will meet withboth being in the horizontal position so that no stop Lmeans isnecessary to prevent the platform portion from going downward past asubstantially horizontal position under the weight of a workman. Bysubstantially Vertical is meant Vertical or within of the Vertical andby substantially horizontal is meant horizontal or within 30 of thehorizontal. Of course it is obvious that it is not necessary for theframe portion of the gangway to be in 'a horizontal position when theplatform is in a horizontal position for use by workmenand therefor itis not absolutely necessary that the gear ratio of the platform gears tothe frame gears be 1:1, but it is preferred that this gear ratio latleast be within the range of 0.5:1 to 1.221.

FIGURE 2 is an isometric View of the type gangway of FIGURE 1 in a.lowered position and also shows side railing 9 and a locking device 10which are desirable features of a gangway constructed in accordance withthe present invention. For the purposes of illustration, only one siderailing 9 has been shown but obviously a second side railing could beplaced on the opposite side of platform 1. These side railings aredesirable from a safety standpoint as they provide protection for menworking on the platform while the locking device 10 serves to lock theplatform in a horizontal position even though a workman has stepped offthe platform. The particular locking device used to hold the platform ina horizontal position is not a part of the present invention 'and 'canbe easily constructed by one skilled in the art. Preferably, theselocking devices are self-engagealble as the platform is placed in thelowered position. When the gangway of the present invention isconstructed as shown in FIGURE 2 such that both the platform and theframe are horizontal when the gangway is in a lowered position,-lockingdevice 10 may be mounted on frame 4 so as to engage a pin 11 or the likeon platform 1. This prevents platform 1 from rotating away from frame 4and thus keeps platform 1 in a horizontal position when there is noweight on platform 1.

It is preferred that any side railings provided for the platform of thegangway of the present invention be foldable so that they areessentially coplanar with the platform portion when the gangway israised, i.e., when .the platform is Vertical. The particularconfiguration of these side railings is not a part of the presentinvention and they may be easily constructed by one skilled in the art.However, the particular side railing 9 shown in FIG- URE 2 may be usedwherein the Vertical and horizontal 'members pivot at all connectingpoints, A, B, C, D, E. and F. Point F is the point of connection of theside railing 9 with a side railing 12 of the tank car loading dock butthis connection could be to any fiXed object other than side railing 12.

The platform portion of the gangway of the present invention 'may be ofvarious shapes and sizes. However. it is preferred that the platformportions be rectangular in shape as shown in FIGURE 2. The platform maybe constructed so 'as to have a solid surface or may be comprised of aframework having a grate for a surface. The frame portion of the presentinvention on which the counterweight is attached may have Various shapesand configurations. It may be comprised of two coplanar parallel barsextending perpendicular to the axis of the gear or gears to which it isattached and having 'a counterweight suspended between these bars asshown in FIG- URE 2 or it could consist of a single structural member(such 'as an I-beam) extending perpendicularly from the axis of the gearor gears and having a counterweight attached thereto at some point fromthe axis. Generally these frames will be constructed so that thecounterweight is adjustable to various positions on the frame.

Although the gangways of the present invention have been illustrated anddescribed in relation to a railroad tank car loading dock, thesegangways may be used to advantage on other structures wherein it isdesirable to have 'a retractable gangway. For example, the gangway ofthe present invention could ybe used in connection with a doorway in theside of a building where the doorway is substantially above groundlevel. Such elevated doorways are common in warehouses wherein trucksare loaded and unloaded. In such cases the platform portion of thegangway can also serve as a door for the doorway when the gangway is ina r-aised position.

What is claimed is:

1. A gangway 'for attaohment to a structure comprising a platform havingat least one first spur gear fixedly 'attached thereto at one end ofsaid platform such that substantially all of said platform extends awayfrom the axis of said first spur gear, said platform being substantiallyparallel to a pliane containing the `axis of said first spur gear, saidfirst spur gear being meshed with at least one second spur gear, saidsecond spur gear being fixedly attached substanti'ally to one end of aframe, extending away from the axis 'of said second spur gear, saidframe having a counterweight secured thereto 'at a distance from theaxis of said second spur gear, both said platform and said frame Ibeingrotatably attached to ya member or members adapted to be mounted on;said structure, said platform being rotatably attachedto said member ormembers so as to rotate about the aXis of said first spur gear and saidframe being rotatably attached to said member or 'members so as torotate about the axis of said second spur gear, said first spur gearbeing meshed with said second spur gear such that said frame will extendsubstantially vertically downward when said platform eX- tendssubstantially vertically upward.

2. The gangway of claim 1 wherein said gangway has a locking means tosecure and hold said platform in a lowered position.

3. The gangway of claim 1 wherein said platform has attached theretoside railings which wi-ll fold to be substantially coplanar With saidplatform n the raised position.

4. The gangway of claim 1 wherein there are two first spur gears and twosecond spur gears, said first spur gears being in axial alignment Witheach other, said second spur gears being in yaxial alignment With eachother, one of said first spur gears meshing with one of said second spurgears, and the other of said first spur gears being meshed with theother of said second spur gears, all of said gears being substantiallythe same size.

5. The gangway of claim 1 wherein said platform is substantiallyrectangular.

References Cited UNITED STATES PATENTS 321,638 7/1385 Ralph 182-811,723,885 8/1929 Patterson 14 71 2,843,865 7/1958 LOOmS 14-71 10 JACOBL. NACKENOFF, Primary Examiner.

